Failed closure of the neural tube, the embryonic structure from which the brain and spinal cord are formed, leads to neural tube defects (NTDs). The NTD complex includes the two most common forms of NTDs, spina bifida and anencephaly, as well as other less frequent manifestations, such as encephalocele, craniorachischisis, and iniencephaly. The frequency of NTD births in the United States is approximately 1/1000, making it the second most common birth defect in humans. Numerous studies have implicated both environmental and genetic factors. The identification of a substantial risk reduction for NTD birth following preconceptional supplementation with folic acid has represented a substantial breakthrough for prevention, but the mechanisms for its action are unclear. Despite decades of study, very little progress in understanding the genetic basis of NTDs and the relationship between genes and the environment has been made. The goal of this proposal is to bring together researchers from a variety of fields, including human genetics, embryology, dysmorphology, epidemiology, animal modeling, nutrition, and molecular biology to share research findings, ideas and goals, and to establish new collaborations and new avenues of research. This conference will provide an ample forum for formal and informal interactions between investigators, and further the collaborative relationships across the world in this discipline.